燃烧室压力对潜入式喷管喉衬热应力的影响

为了研究燃烧室压力对固体火箭发动机潜入式喷管热应力影响规律的问题,采用商业流体软件,基于压力求解器,求解了喷管纯气相的流场,确定了燃气温度、压力、壁面对流换热系数;采用有限元软件,依据流场计算的非均布壁面压力与非均布对流换热,求解了燃烧室压力为6 MPa下的潜入式喷管热结构问题;通过地面点火试验验证了仿真模型与数值方法...     

冲激雷达抗 RAM能力的实验研究

本文用实验方法从频域和时域两个方面研究了涂覆吸波材料目标的电磁散射,结果表明超宽带信号比常规雷达的窄带信号对付涂覆吸波材料目标有10～12dB好处,说明超宽带信号的确具有抗窄带吸波材料的良好能力。     

现代水面舰船结构发展的若干问题

本文综述现代水面舰船结构的若干进展,从舰船结构材料、结构型式以及舰船生存能力等方面进行评述。     

充电法在复合材料静电测试中的问题

按照GJB2605－96中有关静电衰减性能测试的要求,自制了复合材料静电衰减性能测试装置。用这套测试装置对9种不同结构的复合材料进行了实验研究。研究表明,利用充电法测试材料静电衰减性能时,由于电容效应,测试结果不能正确反映被测材料的静电性能。     

A Novel Framework for Safeguarding Naval Nuclear Material

ABSTRACT

The present international standard allows non-nuclear weapon states (NNWS) to forego safeguards when nuclear material is used in a “non-proscribed military activity,” though no criteria have been established to determine when NNWS can remove naval nuclear material from safeguards. Though at present, only nuclear-armed states possess nuclear submarines, the global nuclear naval landscape may soon change with the advancement of Brazil's fledgling program and the possible precedent it would set for other NNWS. A framework is needed to shore up nuclear security and prevent nuclear material diversion from the nuclear naval sector. Proposed and existing nonproliferation frameworks, including a Fissile Material Cut-off Treaty and commitments through the nuclear security summits, are insufficient to close this loophole. A Naval Use Safeguards Agreement (NUSA), modeled after the Additional Protocol of the International Atomic Energy Agency, would provide a framework to remove the opacity surrounding nuclear material in the naval sector. Designed for NNWS and encouraged as confidence-building measures for nuclear weapon states, NUSA would explicitly outline those stages in the naval nuclear fuel cycle where safeguards are to be applied and in what context. This viewpoint also further provides direction for targeted research and development in technical naval nuclear safeguards solutions.     

FACILITATING NUCLEAR DISARMAMENT: Verified Declarations of Fissile Material Stocks and Production

Unprecedented interest in seeking progress toward nuclear disarmament exists today; even some nuclear weapon states are looking for new ways to strengthen this process. National declarations of fissile material holdings—highly enriched uranium and plutonium—could play an important role in supporting this effort, facilitating not only transparency but also the irreversibility of the process. This article discusses what kind of content such declarations could have in order to be meaningful and effective, the sequence of data on fissile material holdings that states might release, and some of the challenges to be expected in reconstructing historic fissile material production; it also summarizes current attitudes of weapon states toward making such declarations. Initial declarations can be valuable as confidence-building measures, but better and more background data are necessary if declarations are to serve as the groundwork for deeper cuts in the nuclear arsenals. A robust verification approach would ultimately require inspectors to have access to fissile material production and storage sites. The methods and tools of nuclear forensic analysis—in this context also dubbed nuclear archaeology—would be a key element of this process. This article discusses the capabilities and limitations of potential approaches to verifying declarations of historic production of plutonium and highly enriched uranium; it also identifies and discusses opportunities for further research and development.     

STRATEGY FOR A NEW NUCLEAR AGE

Current U.S. nuclear weapons strategy, force structure, and doctrine contribute to the threat of nuclear terrorism in several ways. First, the U.S. nuclear stockpile presents opportunities for nuclear terrorists to seize the materials they need. Second, U.S. nuclear forces remain a key justification for Russia's maintenance of similar nuclear forces that are less well protected. Third, America's continued embrace of nuclear weapons encourages and legitimizes other states to seek nuclear weapons that they will have difficulty securing from terrorists. The national security interests of the United States would be better served by a strategy to shrink the global footprint of nuclear weapons and provide the highest possible levels of security for the most minimal possible deterrent forces. Given the inability to secure nuclear weapons and materials perfectly or to eliminate terrorism in the foreseeable future, reducing the global inventory of nuclear weapons and materials is the most reliable way to reduce the chances of nuclear terrorism.     

Technical and proliferation‐related aspects of the dismantlement of Russian Alfa‐Class nuclear submarines

When does a state become a “nuclear weapon state”? How we choose to answer this question has significant implications for proliferation assessment, analysis, and policy. Traditionally, the standard demarcation line has been a state's first nuclear test, but in recent years analysts have increasingly focused instead on the accumulation of a significant quantity (SQ) of fissile material. The article argues that although the test/no-test indicator clearly has problems, its replacement by the SQ/no-SQ indicator would be highly counterproductive. The article instead proposes supplementing the traditional test/no-test indicator with a theory-driven approach that focuses on the incentives and disincentives to test.     

瞬态高强加热条件下含湿多孔介质传热传质模型研究

提出了瞬态高强加热下含湿多孔介质传热传质的新模型,模型包括的水分种类齐全、水分迁移机制全面,假设条件相对较少,考虑了非Fourier传热效应和非Fick传质效应。新模型通过具体的分区分析得到简化并更加实用。     

超磁致伸缩材料特性及其工程应用综述

超磁致伸缩材料是实现电磁能-机械能二者能量和信息高效转换的功能材料。介绍超磁致伸缩材料的特性及器件优异的性能,较全面综述超磁致伸缩材料在各个领域的应用与开发情况,分析开发超磁致伸缩器件需要解决的若干关键技术问题,展望超磁致伸缩材料广阔的应用和发展前景。